1. Field of the Invention
This invention relates to a pneumatic test plug for use for testing water or sewer lines for leaks.
2. Description of the Prior Art
There are a number of different types of pneumatic test plugs in use for testing water or sewer lines for leaks. U.S. Pat. Nos. 2,843,154, 3,129,726, and 4,203,473 disclose several types of pneumatic test plugs. The known pneumatic test plugs on the market have ridges on the outside as shown in U.S. Pat. Nos. 2,843,154 and 4,203,473 (FIG. 9) for enhancing deflation when the air pressure is released. The exterior ridges prevent the plug from being used to test the T of a test pipe whereby the plug is used to test the pipe above the T. This requires one to place his hand up into the pipe for locating and removing the plug and also for disconnecting and connecting the air pressure tube from and to the plug after inflation and for deflation purposes. This presents problems in that the plug may explode and damage one's hand or the plug may be inadvertently left up in the pipe in an inflated position causing subsequent fluid flow problems. In addition, the known pneumatic test plugs do not inflate properly for effective sealing and/or become distorted upon deflation when used in the T. The distortion makes it difficult to remove the plug from the test opening and to reinsert the plug in another test opening which reduces its effectiveness for subsequent use.